JPH0733473B2 - Filled polymer blend - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a novel polymeric mold composition comprising an amorphous polymer matrix and an inorganic filler.
g composition). More particularly, the present invention relates to polymer blends with improved properties, especially reduced coefficient of linear thermal expansion (CLTE), high dart impact resistance, and good thermal activity. The above composition has reduced impact notch brittleness and predictable finish size and smooth finish. It is useful for the production of moldings produced by the injection molding method, in particular parts having a large surface. Such properties are particularly desirable for body exterior panels.

U.S. Pat. No. 4,098,374 discloses a blend of a matrix interpolymer, a graft rubber copolymer, a polymer other than the above two polymers having a solubility parameter in the range of 8.5 to 13, and an inorganic filler. An example of such a blend consisting of ABS resin, about 14% clay and polymethylmethacrylate or cellulose butyrate is disclosed. This reference further teaches that polycarbonate may also be used in the blend.

In Japanese Patent No. 52/63954, ABS resin 20-45 wt%, polycarbonate resin 4.5-20 wt%, and talc 5-30.
Blends consisting of weight percent are disclosed. It has been found that such compositions do not have suitable thermal deformability and, for example, have poor shoe properties as measured by dart impact resistance or notched Izod impact values.

In some applications, such as automotive exterior injection molded parts,
It is desirable to provide one polymer resin with low temperature impact resistance as well as low coefficient of linear thermal expansion and high temperature flex resistance. Linear thermal expansion coefficient (measured by ASTM D696) 21-49 ℃
7.0 × 10 ^-5 / ° C (3.
Unless it is less than 9 × 10 ^-5 / ° F), extreme temperature conditions can result in incompatibility of various elements of the finished assembly. Over-expanding doors or fender elements cause buckling or incompatibility of the assembled finished product in extreme thermal conditions. Impact resistance, as measured by dart impact resistance, especially when the thermoplastic resin undergoes cracking under impact, especially at low temperatures, is also important. Improvements in the coefficient of linear thermal expansion are generally obtained by increasing the amount of filler, but impact resistance, especially low temperature impact resistance, is often reduced to unacceptable levels. Although fiber-reinforced additives such as glass fibers are very effective in lowering the CLTE, such fibers stand out on the surface of the resulting object, thereby producing unacceptable surface properties.

Therefore, it is desirable to provide an improved polymer blend having a low coefficient of linear thermal expansion while retaining an acceptable high dart impact resistance, especially low temperature dart impact resistance, and low notch brittleness.

Further, it is desirable to provide an improved polymer blend that retains the high heat deflection temperature under load so that the parts made therefrom will be exposed to high temperatures without deformation.

According to the invention, the following components: (A) aromatic polycarbonate, 50-80% by weight, in particular
50-80 wt%; (B) Rubber-modified homopolymer or copolymer of vinyl aromatic monomer, 5-46 wt%, preferably 5-46 wt%; (C) (i) Talc or clay charge in final blend Inorganic selected such that at least 98% by weight of the agent particles have a particle size (large size) of less than 44 μm and (ii) an average filler particle size to thickness (large size to small size) ratio of 4-24. Fillers Provided are filled polymer blends containing from 4 to 18% by weight.

The blend has a coefficient of linear thermal expansion (CLTE) of 7.0 × 10 ^{-5 /} ℃ (3.9
× 10 ^-5 / ° F) or less, dart impact resistance [−29 ° C (−20 °
F)] at least 11.3 Joules (100 inch pounds) and
It has a heat deflection temperature under load according to ASTM D-648-82 at 455 kPa (66 psi) of at least 110 ° C (230 ° F).

The method used for measuring CLTE is the method of ASTM D696. Drop dart impact strength is 2.2m / sec (5mile / hr) Spear diameter 1.3cm (0.
5 inch) dart impact strength by the instrument measured according to ASTM D3763-86.

Aromatic polycarbonate resins usefully employed in accordance with the present invention are known to date and described in the prior art. More specifically, such resins include interfacial polymerization of dihydroxyaryl compounds, especially bisdihydroxyarylalkanes, with phosgene or bischloroformate in the presence of methylene chloride and an acid binder such as an alkali metal hydroxide or pyridine. Alternatively, there is a polycarbonate resin obtained by solution polymerization. Particularly suitable aromatic polycarbonates include bisphenol A polycarbonate, tetrabromobisphenol A polycarbonate, and tetramethylbisphenol A.
There are polycarbonates, 1,1-bis (4-hydroxyphenyl) -1-phenylethane polycarbonate and mixtures thereof.

Rubber-modified homopolymers and copolymers of vinyl aromatic monomers include rubber-modified homopolymers of styrene or α-methylstyrene or rubber-modified copolymers of comonomers copolymerizable with styrene or α-methylstyrene. Preferred comonomers are acrylonitrile used alone or in particular in combination with methylmethacrylate, methacrylonitrile, fumaronitrile and / or other comonomers such as N-arylmaleimides such as N-phenylmaleimide. Preferred copolymers include 70-90% styrene, preferably 70-80%
And acrylonitrile 30 to 10%, preferably 30 to 20%.

Suitable rubbers include the well-known homopolymeric copolymers of conjugated gens, especially butadiene, as well as, for example, olefin polymers, especially copolymers of ethylene, propylene; There are homopolymers or copolymers of alkyl acrylates having. Further, a mixture of the above rubber polymers can be optionally used.
The preferred gums are butadiene homopolymers and copolymers of butadiene and styrene up to about 30% by weight. Such copolymers are random or block copolymers and can be further hydrogenated to remove residual unsaturation.

The rubber modified copolymer is preferably produced by a graft generation method such as bulk polymerization, solution polymerization or emulsion polymerization of the copolymer in the presence of the rubber polymer.

In emulsion polymerization to form rubber-based graft copolymers, it is well known in the art to use aggregation techniques to produce large and small rubber particles containing the grafted copolymer. During this process, non-grafted copolymer, various amounts of matrix are also formed. In solution or bulk polymerization of rubber modified copolymers of vinyl aromatic monomers, matrix copolymers are formed. The matrix further comprises rubber particles having the copolymer grafted thereto or occluded therein.

Particularly preferred products include bulk polymerized or solution polymerized rubber-modified copolymers and an additional amount of emulsion polymerized,
There are rubber modified copolymer blends that preferably consist of both agglomerated rubber modified copolymers and that include a type 2 viscosity distribution. The most preferred rubber modified copolymer is a butadiene rubber modified copolymer. The butadiene rubber modified copolymer of styrene and acrylonitrile is technically ABS
Called resin.

To obtain a resulting polymer blend that meets the requirements of the present invention, it is desirable to use a particular concentration of a suitable talc or clay filler having an elongated structure. Spherical fillers are better than elongated fillers in CL of polymer blends produced.
It has now been discovered that it does not have the ability to reduce TE.
Large / small size of packing (diameter / thickness)
Ratio determinations are best performed by first making thin sections by freeze micromming and taking electron micrographs at 3000-15000 magnification.

By measuring the diameter / thickness of a typical sample of at least 25, preferably 50, filler particles, a relatively accurate value of the diameter / thickness ratio can be obtained. 40μ
The percentage of talc or clay filler with a diameter less than m can be measured by screen analysis using a 325 mesh screen. Instead of the average particle size of the filler
The proportion of fillers below 40 μm and below 20 μm can be measured by the use of sedimentation analysis. ASAE Bulletin (Tr
ansaction of ASAE) 491 (1983).

A preferred composition according to the invention is a composition comprising 5 to 15%, preferably 6 to 12% of one or more talc or clay fillers. In a particularly preferred filler, at least 99% by weight of the filler has an average particle size of less than 20 μm.

Highly preferred are compositions containing fillers having an average diameter / thickness ratio of 6 to 18 as measured by the above method. Fillers are uncalcined talc and clay with a very low content of free metal oxides.

Preferred compositions according to the present invention have 55 to 75 wt% aromatic polymer carbonate and 10 to 40 wt% rubber modified homopolymer or copolymer, and have at least 22.6 joules (200 inch pounds) of -29 ° C (-20%). dart impact value in ° ^{F), 6.7 × 10 -5 /℃(3.7+10} -5 / ° F) of less than CLTE,
And a DTUL of at least 121 ° C (250 ° F).

The composition is produced by blending the above components A, B, C. It may be desirable to first mix or dry compound the components prior to melt compounding in a suitable extruder or other melt compounding equipment. The components can be combined and combined in any order. In addition to the above components, the blend can include additional additives such as coupling agents such as the polyfunctional organosilicon compounds disclosed in US Pat. No. 4,528,303. Pigments, antioxidants, processing aids, flame retardants, lubricants, mold release agents, and other additives can also be included in the composition.

Generally, the addition of large amounts of polycarbonate is improved DTUL
Resulting in a final composition having However, the use of excessive amounts of polycarbonate results in reduced dart impact strength. Injection-molded components made from the resin blends of the present invention are generally found to be unexpectedly smooth, have a defect-free surface finish, and have low notch brittleness in impact testing. Further, the composition exhibits improved resistance to hydrocarbon solvents such as gasoline, as compared to polycarbonate resins.

In addition to the above components, additional amorphous polymers can be further incorporated into the polymer blend. Examples of additional polymer components that can be further incorporated into the compositions of the present invention include thermoplastic polyurethanes, amorphous polyesters and polyarylate resins.

Having described the invention, the following experiments further illustrate the invention and should not be construed as limiting the invention. Parts and percentages are by weight.

Experiment 1. Runs 1-4, Comparative Example a A polycarbonate / ABS blend containing 64% by weight of bisphenol A polycarbonate, 36% by weight of bulk polymerized polybutadiene modified ABS resin (including 20% rubber, 23% acrylonitrile and 57% styrene). 99 in circulating air dryers
After drying at ℃ for 4 hours, in a polyethylene bag 0.1% epoxidized soybean oil, 0.1% trisnonylphenylphosphite (TNPP) and various amounts of uncalcined clay [Anglo-Amerian
Available from Clay Company) Tex 10R]
Mixed with. Mix the mixture with Warner
er Pfleiderer) ZSK-30 twin screw extruder. Keep the heating device at 270 ° C (518 ° F),
The screw runs at 400 rpm and the throughput speed is about
It was 13.6 kg / hour (30 lb / hour). The strand was cooled in a water bath and chopped. Next, the grain is placed in a circulating air oven at 99 ° C.
Dry for 4 hours at (210 ° F) and
rg) Melt temperature 288 ° C (550 ° F) in a 28 ton injection molding machine
The test pieces were molded at a mold temperature of 82 ° C (180 ° F).
The physical properties of the resulting injection molded sample were then measured. More than 99.99% of the particles in the resulting blend are 44
It had a diameter of less than μm. The average particle size / thickness was 14.3. The test results are shown in Table 1.

Run 2. Run 5, Comparative Example b The polycarbonate / ABS blend used in Run 1 was compounded with 6% each of two clay samples having the diameter / thickness ratios shown in Table 2. These compositions were also molded substantially according to the method of Experiment 1. The test results are shown in Table 2. A composition comprising clay having an average particle size / thickness ratio of 16.3 is a CLTE 7.8 × 10 ⁻⁵ of a composition comprising clay having an average particle size / thickness ratio of 2.8.
CLTE 6.6 × 10 ^-5 / ° C compared to / ° C (4.28 × 10 ^-5 / ° F)
(3.65 × 10 ^-5 / ° F). All samples have preferred DTUL and dart impact strength at -29 ° C (-20 ° F).

Transmission electron micrograph of a microtome slice of an injection-molded sample in which the packing diameter (maximum size out of two measurable sizes) and packing thickness (minimum size) were exposed to emphasize the packing phase. (7500X). Filler diameter and thickness were measured manually for sample sizes of 20-50 particles.

Run 3. Run 5-13 In the same manner as Run 1, a polycarbonate / ABS blend was compounded with many types of talc with> 99.99% of all particles less than 44 μm. The test results of these samples are shown in Table 3. All samples containing 6-10% talc have favorable values for CLTE and dart impact strength of -29 ° C (-20 ° F).

Experiment 4. Runs 14, 15, Comparative Examples c, d Four blends of talc were blended into the blend of polycarbonate from Experiment 1 and ABS resin in an amount of 6-10%. Drop dart impact test and CLTE produced blends and unmodified polycarbonate / A
Experiments were performed on BS blended 12.5 x 12.5 cm (5 x 5 inch) plaques. The four types of packing are MP-50-26 (D / T = 6.
2, <44 μm particles 98%; <20 μm particles 83%, l ₁ ) Run 14; M
P25-38 (D / T = 9.5, <44 μm particles 99.99%; <20 μm particles 99.5%, l ₂ ) Run 15; MP99-10 (D / T = 5.7, <44 μm particles, 77%; <20 μm particles 58% l ₃ ) Comparative Example C: and MP99-54
(D / T = 1.8, <44μm particles 98.0%; <20μm particles 67%,
l ₄ ) Comparative example d. All talc was obtained from Pfizer. The DTUL value for all samples was 124 ° C (255 ° F). CLTE and dart impact resistance at -29 ° C (-20 ° F) are shown in Figures 1 and 2, respectively.

As can be seen from the reference to FIGS. 1 and 2, increasing the proportion of filler results in a product with reduced CLTE, but also with dart impact strength. Certain packings cannot meet the simultaneous requirements of CLTE 3.9 and dart impact value of -29 ° C (-20 ° F) of at least 11.3 Joules (100lb).

Experiment 5, Runs 16 to 22, Comparative Example e N-Phenylmaleimide Modified ABS Resin and Emulsion A
Polycarbonate was blended with BS resin. The N-phenylmaleimide modified ABS resin contained 19% AN, 6.5% butadiene, 1.3% styrene and 11.5% N-phenylmaleimide and was prepared by solution polymerization of monomers in the presence of dissolved polybutadiene rubber. Next, emulsion ABS containing 50% of polybutadiene rubber obtained by grafting styrene / acrylonitrile (50/50) copolymer on this ABS.
20% was compounded. Polycarbonate has a melt flow rate (melt f
bisphenol A polycarbonate with low rate [Dow Chemical Company
Caliber (CALIBRE ^™ 300-10) available from

Various clay and talc fillers are incorporated into the polymer in amounts of 4-10% by weight. The results are shown in Table 4.

[Brief description of drawings]

Fig. 1 shows the relationship between CLTE and the amount of filler added for the four fillers defined in Experiment 4; Fig. 2 shows the dart impact strength and the fillers for the four fillers defined in Experiment 4. The relationship with the amount of agent added is shown.

Claims (8)

[Claims] 1. The following components: (A) aromatic polycarbonate, 50-80% by weight; (B) rubber-modified homopolymer or copolymer of vinyl aromatic monomer, 5-46% by weight; and (C) (i. ) At least 98% by weight of the filler particles in the final blend have a particle size of less than 44 μm; (ii) a talc or clay filler selected such that the average filler particle size / thickness ratio is 4-24. Thermal expansion coefficient (CLTE), 7.0 × 10 ^{−5 /} ° C. (3.9 × 10
^-5 / ° F) or less, -29 ° C (-20 ° F) dart impact strength of at least 11.3 Joules (100 in-lbs) and 66p
A filled polymer blend having a heat deflection temperature (DTUL) of at least 110 ° C (230 ° F) under load at si (455 KPa). Wherein CLTE 6.7 × 10 ^-5 /℃(3.7×10 ^-5 / ° F) the polymer blend of claim 1 having the following. 3. The polymer blend of claim 1 having a dart impact strength at −29 ° C. (−20 ° F.) of at least 22.6 joules (200 inch pounds). 4. The polymer blend of claim 1 wherein at least 99% of the filler particles have a particle size less than 20 μm. 5. The polymer blend of claim 1 in which the filler has an average diameter / thickness ratio of 6-18. 6. The polymer blend of claim 1 wherein the filler is selected from the group consisting of talc and green clay. 7. A rubber-modified copolymer comprising a copolymer of styrene and acrylonitrile and optionally N-phenylmaleimide, the rubber being a homopolymer or copolymer of butadiene, or an interpolymer of ethylene, bropyrene and a non-conjugated gen. 1. The polymer blend according to 1. 8. A processed article comprising the polymer blend of claim 1.